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We would like you to take the following benchmark scores
with a grain of salt, sugar or whatever it is that helps you
digest things more easily. Please keep in perspective
that the following tests are based on a benchmark suite that
performs real-world functions like JPEG decompression, etc.
However, the tests are not based on any end user
retail applications but rather a "synthetic" collection of specific
computational functions.
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PCMark 2002
Testing |
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Synthetic benchmarks that show
huge potential for Hyperthreading |
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Here we see that the Pentium 4
3.06GHz scales accordingly in performance versus the 2.8GHz
chip, with roughly an 8% lead. However, overall the
CPU test does not show any benefit for the Hyperthreading
enabled system. That is until we look more closely at
the "Crunch" test section.
We asked the folks at
MadOnion
to give us a little background on what was behind the
"Crunch" test in PCMark 2002. Here's what Patric Ojala,
Senior Manager, Benchmark Development
at
MadOnion.com told us.
The Crunch
test runs 3 tests simultaneously:
CPU Test - JPEG Decompression, stressing mostly the CPU and
somewhat
also the memory subsystem.
Memory Test - Raw 3072 kB Block Modify, stressing mostly the
memory
subsystem, but also somewhat the CPU.
Memory Test - Video - 1 scanline, stressing mostly the
graphics card
memory bandwidth and the AGP bus.
These tests are all described above, and can be run
separately in PCMark2002. The idea of the Crunch test
is to see how well the system can perform several tasks
simultaneously and stress different parts of the system
concurrently. The Crunch test was designed to be a
stress test for total system throughput; CPU, Memory
and Graphics speed. This kind of measurement
should be good for total system comparison, multiprocessor
benchmarking, and motherboard chipset efficiency
testing. The included tests were selected because:
CPU Test - JPEG Decompression, since it is a CPU intensive
test that does a task common for many applications (web,
office, image composer). The data set is larger than
what fits into the cache, so there is some memory transfer
involved, which is appropriate for any CPU test.
Memory Test - Raw 3072 kB Block Modify, where the large
block is used to avoid only cache measurement. The block
modify functionality is typical for data modification, like
a light Photoshop filter. The data operation is light enough
to stress above all the memory read and write speed.
Still, just data transfer back and forth might open up a
chance for caching. Therefore the small modify operation was
included.
The Video Memory test above all stresses the AGP bus and the
graphics card memory speed. The selected single scanline
transfer weights more on the video memory speed than the AGP
speed (compared to the multiple scanline tests), but we
think this kind of smaller video memory data transfer is
more common in PC home and office usage.
The three
threads all have normal priority, so we don't try to control
which part of the system runs most efficiently. We use
pre-set work amounts on all tests, so on many single
processor systems you can see how the CPU and memory threads
complete their tasks first. The video memory test
first scrolls really slowly, while the other tests are
running. Then it suddenly picks up speed and the scrolling
gets smooth, when only the video memory test remains.
No "internally SMP" processors were around when we made
PCMark2002.
In every case
during the Crunch test, we see the Hyperthreaded Pentium 4
blow by it's non HT enabled counterparts with ease.
The Crunch Blit test shows orders of magnitude more
performance for the Pentium 4 3.06GHz with HT enabled.
This could indeed be a foreshadow of things to come with
respect to multithreaded scenarios, like those that were
arranged in the PCMark 2002 Crunch test. Remember, the
folks at MadOnion did not specifically code the benchmark to
take advantage of the HT enabled P4. They told us the
chip wasn't even around when they designed their benchmark.
Regardless, synthetic benchmarks need to be kept in
perspective as the relative performance metrics that they
are.
Let's get back
to the "real world". Well sort of...
Quake
3 Time Demos and UT
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